https://doi.org/10.1140/epjd/s10053-026-01185-0
Research - Photon
Generation of elliptically polarized high-order harmonics using few-cycle pulses with one or two carrier frequencies
1
Faculty of Science, University of Sarajevo, Zmaja od Bosne 35, 71000, Sarajevo, Bosnia and Herzegovina
2
Academy of Sciences and Arts of Bosnia and Herzegovina, Bistrik 7, 71000, Sarajevo, Bosnia and Herzegovina
a
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Received:
12
February
2026
Accepted:
11
May
2026
Published online:
30
May
2026
Abstract
Using the strong-field approximation, we study the generation of elliptically polarized high-order harmonics driven by few-cycle laser pulses with one or two carrier frequencies. In the few-cycle regime, sub-cycle electron dynamics strongly modifies the harmonic spectra and their polarization, leading to pronounced dependence on the pulse duration, carrier-envelope phase (CEP), and driving-field polarization. For monochromatic pulses, elliptically polarized harmonics are produced by elliptically polarized field. High-harmonic yield for elliptically polarized laser field rapidly decreases for atomic targets. For molecular targets harmonic ellipticity can be substantial even for linearly polarized driving pulses. Notably, the harmonic ellipticity displays abrupt changes for molecular orientations associated with destructive interference minima, providing robust, CEP-insensitive structural signatures. For bichromatic pulses, we demonstrate enhanced control of spectral and polarization properties: linearly polarized 
–
field generates highly CEP-dependent multi-plateau spectra, whereas counterrotating elliptically polarized fields yield harmonics with significant ellipticity and moderate intensity. Our results establish few-cycle and two-carrier-frequency driving schemes as versatile tools for polarization control and polarization-resolved high-harmonic spectroscopy.
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© The Author(s), under exclusive licence to EDP Sciences, SIF and Springer-Verlag GmbH Germany, part of Springer Nature 2026
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
